Alto de Isasmendi

Overview

Alto de Isasmendi is a compact category 4 climb that packs its work into just 4 km. It begins at 594 m and finishes at 762 m, so you gain 168 m of altitude from bottom to top. The average gradient sits at a friendly 4.25%, and the steepest ramp never bites harder than 6.08%. This is the kind of climb that flatters a strong rider and welcomes a developing one — long enough to feel like a real effort, short enough that you can commit early without fear of blowing up. With a total ascent of 147 m recorded along the road, the profile is consistent rather than punishing.

How the Gradient Unfolds

The numbers tell a clean, honest story. Over 4 km the road lifts 168 m in net terms, which pencils out to that 4.25% average. Because the maximum is only 6.08%, there are no cruel surprises hiding around a corner — the gap between average and max is small, meaning the gradient stays close to its mean for most of the ascent. Expect a climb that settles into a rhythm quickly. Where the total ascent (147 m) sits below the net gain (168 m) hints at a road that keeps trending upward without meaningful descents to recover on, so you climb almost every metre you're given. Treat it as a sustained tempo effort rather than a series of walls.

Pacing Notes

Because the gradient is so even, this is a climb best ridden as a controlled threshold effort. Sit just under or right at your FTP and hold it — the modest 6.08% max means you rarely need to surge out of the saddle, so smoothness wins. Riders who don't know their threshold can get a quick figure from the FTP estimator before pacing this one. With only 4 km to cover and 168 m to gain, the temptation is to go out hard; resist it for the first kilometre, then build. On a climb this short there's little margin to recover from an early overcook, so bank your effort into the second half where the summit at 762 m is already in reach.

Gearing

For most riders a compact setup handles Alto de Isasmendi comfortably. A 34×32 gives plenty of range for the 4.25% average and the 6.08% peak, letting you spin a high cadence without grinding. If you prefer to sit and turn the pedals over on any longer sustained stretch — or you're carrying fatigue — a 34×34 adds a touch more insurance and keeps your legs fresh across the full 4 km. Neither ramp on this climb demands anything more aggressive, so the choice comes down to your climbing style and how fresh your legs feel.

Summary

Alto de Isasmendi is a well-mannered category 4 climb: even gradients, a manageable maximum, and a summit that comes quickly. Ride it at tempo, gear sensibly, and enjoy the 168 m of clean climbing.

Length: 4 km
Average gradient: 4.25%
Max gradient: 6.08%
Start: 594 m
Summit: 762 m
Net gain: 168 m
Total ascent: 147 m
Category: 4